Cellular panel and method and apparatus for making the same

ABSTRACT

An expandable and contractible cellular panel  10  comprises a plurality of parallel, aligned, elongated tubular sections  12  secured together at the median region of their adjacent longitudinal margins to form the panel  10 . The adjacent tubular sections  12  of the panel  10  are made of a pair of substantially identical separate strips of sheet material from those forming the other adjacent tubular sections  12 . The various adjacent pairs of strips are laminated together along their confronting longitudinal margins. Each strip is made of at least two separate flexible substrate sheets  18,20  having completely different appearances, and are secured together by welding together their longitudinal margins. The corresponding substrate sheets  18,20  of all the strips have corresponding positions in the panel  10 , so that all the substrate sheets having one appearance are on one side of the panel  10  and those having a different appearance are on the other side of the panel  10 , and the welded portions  28,28 ′ are located in the laminated portion of the strips where they are hidden from view.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to cellular insulation panels. Ithas one of its most important applications as an insulating panel forcovering windows or other openings. These panels most commonly comprisea plurality of tubular sections adhesively secured together. The panelcan be oriented so that the tubular sections form a horizontallycontractible and expandable panel which extends vertically, such as whencovering a doorway or other similar openings. The panel more commonly isused with an orientation where the tubular sections form a verticallycollapsible and expandable panel extending horizontally, such as whencovering a window.

[0002] In window covering, the panel is mounted upon a headrail withpull cords extending down through holes in the panel to a bottom railsecured to the bottom of the panel. In some panel designs, each tubularsection is a strip of usually thermoplastic woven or unwoven sheetmaterial folded into an open-top tube. Each tube-forming strip isinitially completely separate from the other tubular strips forming thepanel and is laminated to the adjacent strips of the panel by bands ofadhesive. The folds of each tubular section are usually sharp or set sothat they appear as lines or bands which improve the aestheticappearance of the panel. Such a panel is disclosed in Dutch PublishedApplication No. 6706563 published Nov. 11, 1968 to Landa. In this Dutchpublication, the cells have a rectangular, hexagonal or a pointed ovalshape, depending on the width of the adhesive bands and the degree ofexpansion of the cells. If the adjacent tubular sections are securedtogether over wide securement bands and are fully expanded, the cellshave a rectangular shape, as is shown in U.S. Pat. No. 4,019,554 grantedon Apr. 26, 1977 to Rasmussen.

[0003] In another form of cellular panel construction, a pair of zig-zagshaped sheets of material are placed into confronting relation andsecured together at the abutting fold points, to form diamond-shapedcells. This panel construction is disclosed in U.S. Pat. No. 2,201,356granted Nov. 21, 1938 to Terrell.

[0004] The rear side of all these cellular panels, which interrupt thepassage of light when covering a window, preferably have a color toreflect light. The front side of the panels, which face into the roominvolved, desirably have an appearance from a strictly aestheticstandpoint. In the panel design where each tubular section is made of aseparate sheet of material folded into a tube, one half of the sheet maybe printed or embossed before it is folded into a tubular shape, so thatthe portion of each sheet which faces the inside of the room is providedwith the desired aesthetic appearance. The other half of each sheet,which faces towards the window has color to reflect light. If theinitial sheet of material is already of a desired light color to reflectlight, it can remain without any added coloring. If the sheet formingeach tubular strip is made of an expensive material to give the frontside of the panel an attractive appearance, the high cost of the portionof the same sheet which is to face the window is an undesired expense.

[0005] The panel design having diamond shaped cells, describedpreviously, made from a pair of separate, confronting zig-zag shapedsheets does not have this problem as only the front sheet must be madeof the more expensive material. However, this type of panel is lessattractive to some purchasers than the panel having pointed oval,hexagonal or rectangular cells. Also, the method required forfabricating the panel made from zig-zag shaped sheets is less efficientand more difficult to control than the method used to make a panel ofseparate folded strips of material adhesively secured together.

[0006] The preferred cellular panel constructed and manufactured inaccordance with the present invention overcomes these disadvantages. Thepanel can have cells of any desired shape, and can be made by a veryefficient stacking process. In addition, only the front side of thepanel requires a more expensive material, satisfying the aestheticobjectives of purchasers, and thus, the rear side can be made of a lessexpensive material, which is only required to reflect light, and aid informing an insulating panel.

[0007] Many of the present features of the invention are applicable toanother type of panel to be referred to as a light-controlling cellularpanel, which is used to cover primarily windows. In this panel, thefront vertical side of each horizontally extending cell is made of asheer material, preferably of one mesh size, and the rear vertical sideof each cell is made of a sheer material preferably of a different meshsize or mesh shape, to avoid a Moire effect. When the panel is in itslight-passing state, the upper or lower horizontal wall of each cell isa horizontal opaque wall which, most desirably, is wider than the heightof the cell. When one of the vertical sides of the panel is shiftedupward or downward with respect to the other vertical side of the panel,the opaque walls are pivoted into substantially vertical positions wherethey completely overlap, to obstruct the passage of light through thepanel.

[0008] Most of the methods previously used to fabricate this type oflight-controlling panel did not permit the ready manufacture of anydesired width of the panel. The commercial forms of this panel have beenusually constructed from two horizontally spaced confronting unfoldedvertical sheets of sheer material, which respectively formed thecomplete front and rear sides of the panel. Opaque strips of materialare adhesively secured at spaced vertical points between the front andrear sheer sheets of the panel. The cells of this panel have arectangular shape. As will later be described, the present inventionprovides a very efficient and effective means for manufacturing a panelhaving a similar appearance to this panel, but is constructed muchdifferently. The present invention is made from a multiplicity ofseparate identical strips of material of any desired length, cut from acontinuous web and laminated by an efficient strip stacking processwhere the panel can have any desired length. The panel can then be madeinto any width using a highly efficient stacking process.

SUMMARY OF THE INVENTION

[0009] It is preferred in all forms of the invention that the cellularpanel be made by a method and with apparatus that initially is either acontinuous tubular or flat web formed from two or more narrow,continuous substrate sheets or webs of completely different materialwhich form the front and the rear walls of the cellular panel to be madetherefrom. The continuous substrate sheets, when made of a thermoplasticmaterial, are secured together, preferably by sonically welding theirabutting longitudinal margins. This permits efficient mass production ofpanels of various constructions by cutting strips from the web andlaminating the strips together in the various ways to be described.

[0010] One form of the invention forms a panel which is notlight-controlling. The panels are made at a high-speed, on one or moreproduction lines by feeding a pair of basic webs, or substrate sheets,in superimposed relation past one or more sonic welders. Where one sonicwelder is used to make such a panel, the two continuous substrate sheetsare welded together only along one of their longitudinal margins. Theresulting two-substrate web is first unfolded to form a flat web. Theflat web is fed, immediately and sequentially to folding,adhesive-applying, web cutting and stacking apparatus, or to a differentproduction line when wound on a take-up reel and later unwoundtherefrom. The open tubular segments of the web formed by the foldingapparatus produce adhesive connected tubular sections of the completedpanel.

[0011] To avoid unfolding and folding the web, the web is formed by apair of sonic welders which weld both aligned longitudinal margins ofthe superimposed continuous substrate sheets, so that the two-substrateweb formed thereby forms a flat, closed tubular web; the welds are atthe outer edges of the web. The flat, closed tubular web is fed to a webreforming apparatus. This apparatus first opens and then reflattens theweb, so that the welds are transitioned to the flat top and bottom facesof the web. This reformed web is then subsequently fed to theadhesive-applying, web-cutting and stacking apparatus.

[0012] This web-reforming apparatus reflattens the tubular web in aplane preferably less than 90° from the original plane of the flattubular web. This brings the welded margins of the flat tubular web fromthe outer edges of the flat web to laterally offset positions on theflat top and bottom faces of the web. As longitudinally-spaced segmentsof this flattened web become the separate tubular sections of thecompleted panel, the welded portions of these tubular sections arelocated along the confronting faces thereof, which are not visible atthe front or rear side of the completed panel. The two differentappearing substrate sheets are then only visible respectively on theopposite sides of the panel. While in accordance with a broad aspect ofthe invention, the welded portions need not be laterally offset, it isdesirable because the offset reduces the thickness of the panel when itis raised into a collapsed condition at the top of a window. In allapplications of the present invention where the substrate sheets aresonically welded along their superimposed abutting margins, it isdesirable to flatten the welded portions of the substrate sheets. Thisprocess assures only a slight bulging of the substrate material therein,further reducing the thickness of the panel when in its collapsedconfiguration.

[0013] The welding and flattening of the substrate sheets is preferablyachieved by a sonically welding method similar in some respects to thatdisclosed in U.S. Pat. No. 4,177,100 granted on Dec. 4, 1979 toPennington. This patent discloses the use of heat and pressure to firstsecure together the folded trailing edge of a stationary thermoplasticsheet to the superimposed folded leading edge of a following stationarysheet. The welded superimposed stationary sheets are then unfolded andflattened by application of heat and pressure, while the sheets arestretched to pull the welded sheets apart. In the present invention, itis not necessary to pull the welded sheets apart during the applicationof the heat and pressure. In the practice of a preferred form of thepresent invention, the heat and pressure used to flatten the welds areapplied by using sonic welding apparatus designed to perform only aweld-flattening operation.

[0014] In these two methods of making cellular panels, the individualtubular sections which form the completed panel can be formed fromstrips traversely cut from an adhesive coated web either before or afterthey are stacked. The latter stacking method is disclosed in U.S. Pat.No. 4,450,027 to Colson where, initially, an adhesive coated opentubular web, which is not a sonically-welded tubular web of differentsubstrate sheets as just described, is spirally wound on a flat,rotating stacker. The stacker forms a flattened spiral winding of theweb material, where the layers are adhesively secured together. The endsof this flat spiral winding are then severed from the rest of the stackof severed layers of material to separate and divide the severed webinto separate, adhesively-secured together tubular sections forming acontinuous cellular panel. However, it is preferred that theadhesively-coated, multi-substrate web be first cut into strips and thenstacked in a manner like that disclosed in U.S. Pat. No. 3,713,914 toClark et al.

[0015] When forming a light-controlling panel, the initial continuousweb is constructed preferably of three, differently-appearing substratesheets welded together at their confronting longitudinal margins. Thecentral substrate sheet is made from an opaque material. The other twosubstrate sheets positioned on opposite sides of the opaque centralsubstrate sheet, are made from a narrower sheet of sheer materialpreferably of different mesh size or mesh shape, to eliminate a Moireeffect. The three-substrate web is preferably made by positioning one ofthe narrower sheer substrate sheets over and along one of the sidemargins of the wider opaque substrate sheet and positioning the othernarrower sheer substrate sheet beneath the wider opaque web along theopposite side margin thereof. These substrate sheets so positioned aremoved past a pair of sonic welders positioned along the oppositelongitudinal margins of the substrate sheets, where each welder weldsonly the two layers of sheet material located thereat. The resultingthree-substrate web is then unfolded so that the completed panel can bemade by one of two methods.

[0016] In both of these methods, the three-substrate web is initiallycut into strips of equal length. In another method, before the web is socut, it is folded into an open tubular web by folding the oppositelongitudinal margins of the outer sheer substrate sheets of the web overthe central opaque substrate sheet of the web. A pair of adhesive bandsare then applied to the top surfaces of the folded-over portions of thetubular web so that the tubular strips cut from the web are adheredtogether when stacked over a width equal to the width of the opaquesubstrate sheets thereof. The stacked, adhered strips are cut to size toform a continuous cellular panel of desired length.

[0017] When the panel is oriented so that the tubular sections or cellsof the panel extend horizontally and are in vertically-spaced relation,the front wall of each cell is formed by a front vertical sheersubstrate sheet of one of the tubular strips, the rear wall of each cellis formed by a rear vertical sheer substrate sheet of the same tubularstrip, the bottom wall of each cell is formed by a horizontal centeropaque substrate sheet of the same tubular strip and the top horizontalwall of each cell includes the folded end portions of the same tubularstrip and the opaque substrate sheet of the strip above it.

[0018] When the substrate sheets which form the front or rear sides ofthe panel are shifted up or down with respect to each other, theinitially horizontal opaque substrate sheets of the various laminatedstrips are shifted from a horizontal position where light passes throughthe panel to an inclined vertical position where the opaque substratesheets of adjacent strips overlap, to stop the passage of light throughthe panel.

[0019] Another method for fabricating a light-controlling cellular paneleliminates the folding of the initially flat three-substrate webs.Before the flat web is cut into strips, spaced bands of adhesive areapplied to the top surface of the web in a pattern which effects aspecial strip laminating pattern. The adhesive-coated flat web is thentransversely cut into flat strips of equal length. The strips arelaminated together by sequentially laterally shifting the strips fromtheir original aligned longitudinally spaced positions. Each laterallyshifted strip is next laminated so that the outer longitudinal margin ofone of the outermost light-passing substrate sheets of each strip isadhered to the strip cut before it at the innermost longitudinal marginof the corresponding light-passing substrate sheet thereof, and theinner longitudinal margin of the other outermost light-passing substratesheet of the former strip is adhered to the latter previously cut stripat the outer longitudinal margin of the corresponding outer substratesheet. The resulting panel formed from the laterally-shifted laminatedstrips, when expanded, places the light-passing substrate sheets inpositions where one of the light-passing substrate sheets of each stripforms a vertical front wall of an expanded tubular section of the panel,the other light-passing substrate sheet of the same strip forms avertical rear wall of the adjacent expanded tubular section of thepanel, and the opaque substrate sheet of that strip forms the horizontaltop or bottom wall in common between adjacent cells of the panel.

[0020] When the light-passing substrate sheets on one side of the panelare shifted vertically relative to the light-passing substrate sheets onthe opposite side thereof, the opaque central substrate sheet of eachlaminated strip of the panel is pivoted from its initial horizontalposition where light can pass through the panel to a position where theopaque substrate sheets of adjacent cells of the panel overlap oneanother to obstruct the passage of light through the panel.

[0021] Other advantages and features of the invention will becomeapparent upon making reference to the specification, claims, anddrawings to follow.

DESCRIPTION OF DRAWINGS

[0022]FIG. 1 is a perspective view of two adjacent tubular sections ofthe preferred panel of the present invention which is adapted forapplications where the panel covers a window in its normal use and israisable to the top of a window when not in use;

[0023]FIG. 1A is a fragmentary, enlarged vertical sectional view throughthe laminated portions of two adjacent tubular sections of the panel andshows spaced adhesive bands which secure together the adjacent wallsections of these tubular sections of the panel;

[0024]FIG. 2 is a larger perspective view of one of the tubular sectionsshown in FIG. 1, specifically showing the adhesive bands on the top ofeach tubular section;

[0025] FIGS. 3A-3F respectively show the different operations performedon a production line upon a pair of superimposed continuous substratesheets of different material to form a multi-substrate sheet web whichis wound upon a reel and then subsequently unwound and applied to thesecond section of a production line, shown in block form in FIG. 5,where the web is coated with adhesive and cut into strips which are thenlaminated to form a continuous cellular panel;

[0026]FIGS. 4 and 4′ taken together show an exemplary production linefor performing the various steps illustrated in FIGS. 3A-3F;

[0027]FIGS. 4A and 4B disclose slit/weld sensor pins which detectwhether the slit/weld anvils are operating properly;

[0028] FIGS. 4C-4H disclose various views of the web reforming stationsof the apparatus of FIG. 4′, where an initially formed flattened tubularweb is reformed into a tubular web flattened in a different plane;

[0029]FIG. 4I is a transverse vertical sectional view along section line4I-4I in FIG. 4′ through an ultrasonic horn assembly which sets a sharpfold in the side edges of the preformed web;

[0030]FIG. 4J is a perspective view showing in more detail a portion ofthe stress-relieving station of the production line of FIG. 4′, whichincludes a heated cambered plate over which the re-formed web is fed;

[0031]FIG. 4K is a longitudinal vertical sectional view along sectionline 4K-4K in FIG. 4J through a pair of drive and nip rollers at one endof the cambered plate;

[0032]FIG. 4L is a transverse vertical sectional view along section line4L-4L in FIG. 4K through the nip roller assembly;

[0033]FIGS. 4M and 4N show a modification of the production line of FIG.4, where a number of multi-substrate webs are simultaneously formed on anumber of production lines formed of common elements as in FIGS. 4 and4′;

[0034]FIG. 4P shows the different elements of a sonic horn usedthroughout the production lines to be described hereafter;

[0035]FIG. 5 is a block diagram showing how a multi-substrate web formedby the production line of FIGS. 4 and 4′ is further processed byapplying adhesive to the web, cutting the web into strips, and thenstacking the strips to form a completed continuous cellular panel;

[0036]FIG. 6 is a perspective view of two adjacent tubular sections of apanel where each tubular section is an open top tube for a panel whichcovers a window in its normal use and is raisable to the top of a windowwhen not in use;

[0037]FIG. 6A is a fragmentary enlarged vertical sectional view throughthe laminated portions of two adjacent tubular sections of the panel ofFIG. 6 and shows spaced adhesive bands which secure together theadjacent wall sections of the tubular sections of the panel;

[0038]FIG. 7 is a larger perspective view of one of the tubular sectionsshown in FIG. 6, specifically showing the adhesive bands on the top ofeach tubular section;

[0039] FIGS. 8A-8F respectively show the different operations performedon a production line upon a pair of superimposed continuous substratesheets of different material to form a multi-substrate sheet web whichis wound upon a reel and then subsequently unwound and applied to thesecond section of a production line where the web is folded, coated withadhesive and cut into strips which are then laminated to form thecontinuous cellular panel shown in FIG. 6;

[0040]FIG. 9 shows part of a production line for performing the varioussteps which form the multi-substrate sheet web of FIGS. 8A-8F;

[0041]FIG. 10 is a block diagram showing how the multi-substrate webformed by the production line of FIG. 9 is further processed by foldingthe multi-substrate web, applying adhesive to the web, cutting the webinto strips and then stacking the strips to form a completed continuouscellular panel of FIG. 6;

[0042]FIG. 11 is a perspective view of three adjacent cells of yetanother embodiment of the present invention which is a light-controllingcellular panel and is adapted to applications where the front and rearsides of the panel are movable vertically relative to one another fromthe light-passing position of FIG. 11 to one (not shown) where lightpassage through the panel is blocked;

[0043] FIGS. 11A-11B more clearly show the spaced bands of adhesivewhich secure together the adjacent cells or tubular sections of FIG. 11;

[0044] FIGS. 12A-12D respectively show the different operationsperformed on a production line upon three superimposed continuoussubstrate sheets of different material to form a multi-substrate sheetweb which is to form a light-controlling cellular web which is woundupon a reel and then subsequently unwound and applied to the secondsection of a production line shown in block form in FIG. 14, where theweb is folded, coated with adhesive, and cut into strips which are thenlaminated to form the continuous cellular panel of FIGS. 11 and 12;

[0045]FIG. 13 shows part of a production line for performing the varioussteps which form the multi-substrate sheet web of FIGS. 12A-12D;

[0046]FIG. 14 is a block diagram showing how the multi-substrate webformed by the production line of FIG. 13 is further processed by foldingthe multi-substrate sheet web, applying adhesive to the web, cutting theweb into strips and then stacking the strips to form the completedcontinuous cellular panel of FIG. 11;

[0047] FIGS. 14A-14D illustrate the tubular web produced by theproduction line of FIG. 13 respectively, before the web is folded, afterit is folded, after adhesive is applied to it, and after strips cut fromit are laminated together;

[0048]FIG. 15 is a perspective view of a plurality of cells of anotherlight-controlling panel embodiment of the present invention;

[0049] FIGS. 15A-15B are fragmentary enlarged views of the panel of FIG.15 showing the adhesive bands connecting adjacent multi-substrate stripswhich form the cells of the panel;

[0050]FIG. 16 is the multi-substrate web produced by the production linein FIG. 13 coated with bands of adhesive;

[0051]FIG. 17 shows a plurality of strips cut from the web of FIG. 16and laterally shifted with respect to each other, with arrows indicatingthe points where the adhesive band coated on the strip will adhere thelaterally shifted strips together, to form the light-controllingcellular panel of FIG. 15;

[0052]FIG. 18 is a block diagram showing how the multi-substrate webformed by the production line of FIG. 13 is further processed to formthe light-controlling cellular panel of FIG. 15; and,

[0053]FIG. 19 shows the strip delivery and lateral strip-shiftingconveyor means used to laminate the multi-substrate strips together toform the light-controlling cellular panel of FIG. 15.

DETAILED DESCRIPTION OF THE PRESENT INVENTION The Embodiment of FIGS.1-5

[0054] While this invention is susceptible of many different forms,there is shown in the drawings and will herein be described in detailvarious preferred embodiments of the invention, with the understandingthat the present disclosure is to be considered as an exemplification ofthe broad principles of the invention and is not intended to limit thebroad aspects of the invention to the embodiments illustrated. Thevarious different details of the various embodiments of the inventionare, in some cases, due to their different applications and, in othercases, due to progressive improvements to earlier developed embodiments.

[0055] Referring now to the drawings, FIG. 1 shows a portion of anon-light controlling closed tube cellular panel 10 in its expandedstate, formed from laminated horizontally elongated vertically alignedtubular sections or cells 12. This is the most preferred panelembodiment of the present invention where the panel is notlight-controlling as are other panels to be described. FIG. 2 shows asingle cell or tubular section 12 of the cellular panel 10. The cell 12has a front wall portion 14 made from a first continuous thermoplasticsubstrate sheet 18, having a desired aesthetic appearance, and a rearwall portion 16 made from a second continuous thermoplastic substratesheet 20 of about the same thickness, length and width as the firstsheet 18. The second sheet 20 is made of different appearing, preferablymuch less expensive, light-reflecting material from the substrate sheet18. The cell 12 also has a top wall portion 15 and a bottom wall portion17. Each tubular section 12 is laminated to the next adjacent tubularsection 12 by spaced bands 11-11′ of adhesive which are spaced apart toprovide an adhesive-free band 15 a centered on the top wall portion 15of each cell 12 to receive a drill for drilling pull cord-receivingholes (not shown). Folds 13-13′, shown in FIG. 1A, are formed in thecenters of the sheets 18 and 20, so that when the tubular sections 12are expanded by the weight of a bottom rail (not shown) and the weightof the panel itself above the rail, the cells have a hexagonal shape.

[0056] The cell 12 is initially formed by first superimposing the twoseparate continuous substrate sheets 18,20 as shown in FIG. 3A. Thesuperimposed substrate sheets 18 and 20 have superimposed longitudinalmarginal portions adjacent their longitudinal edges 22,22 and 22′,22′which are secured together, most preferably by sonic welding. As shownin FIG. 3B, circular pointed slit/weld anvils 24,24′ are positionedslightly inward of the aligned pairs of longitudinal edges 22,22′ of thetwo substrate sheets 18,20. The anvils 24,24′ may be driven by a pulleysystem (not shown) or other drive means or can be stationary. Drivenrotary anvils are preferred to lessen the wear on the anvils. Theperiphery of each anvil 24,24′ is tapered on each side 24 b,24 b′ towardthe pointed edge 24 a,24 a′ thereof. A common ultrasonic horn 26 havinga flat end face 26 a is positioned under the second substrate sheet 20and extends at least the entire width of the two substrate sheets 18,20.As the two substrate sheets 18,20 pass between the slit/weld anvils24,24′ and the common ultrasonic horn 26, the longitudinal marginalportions of the sheets inwardly of the pointed edges 24 a,24 a′ of theanvils 24,24′ are welded together by the ultrasonic horn 26 vibratingthe two substrate sheets 18,20 against the slit/weld anvils 24,24′.Narrow continuous longitudinal welded portions 28,28′ are formed at theinside faces 24 b,24 b of the slit/weld anvils 24,24′. The weldedportions 28,28′ have a width of about the thickness of each of thesubstrate sheets 18,20. FIG. 3C is an enlarged view of a weld formed bythe process shown in FIG. 3B and shows the pointed edge 24 a′ of theanvil 24′, the superimposed substrate sheets 18,20, and a portion of theultrasonic horn 26 positioned therebelow.

[0057] In addition to sonically welding the superimposed substratesheets 18,20 together, the slit/weld anvils 24,24′ also slit through thesuperimposed substrate sheets 18,20 at the location of the anvil pointededges 24 a,24 a′. This produces selvedge portions 32,32′ of thesuperimposed substrate sheets 18,20 adjacent the pointed edge 24 a,24 a′of each slit/weld anvil 24,24′ which are collected in a process to bedescribed in more detail.

[0058] The welding process described forms a continuous, flat,multi-substrate tubular web 30 (FIG. 3B) in a horizontal plane, with thedifferent appearing substrate sheets 18,20 constituting the oppositeflat sides thereof. The panel 10 is formed from longitudinally spacedsegments cut from this web 30 and laminated preferably in a manner to bedescribed. The web 30 shown is reformed so that a flat tubular web 30′(FIG. 3F) is formed having the welded portions 28,28′ thereof on the topand bottom of the opposite flat sides of the reformed flattened web 30′.To this end, the tubular web 30 is first guided from a horizontal planeto a vertical plane (FIG. 3D). The flat tubular web 30 is next openedand then flattened in a plane approaching a right angle to the originalplane of the flat web 30 to bring the welded portions 28-28′ to the flattop and bottom faces of the reformed tubular web 30′, but laterallyspaced in opposite directions from the center line of the web so thewelded portions 28-28′ webs are not in alignment, as shown in FIG. 3E.As there shown, the reformation of the web 30 causes the welded portions28-28′ to project above and below the top and bottom faces of thereformed web 30′. It is desirable that the reformed tubular web 30′ havea similar thickness throughout; therefore, the projecting weldedportions 28-28′ of the tubular web 30′ are flattened to produce atubular web 30 with similar thickness throughout as shown in FIG. 3F.

[0059]FIG. 3E illustrates this weld flattening process which utilizes aweld flattening ultrasonic horn 33, similar to the welding ultrasonichorn 26 shown in FIG. 3B, but positioned above the reformed tubular web30′, and a preferably driven cylindrical rotating anvil 34 positionedbelow the reformed tubular web 30′. As the tubular web 30′ passesbetween the web flattening ultrasonic horn 33 and the cylindricalrotating anvil 34, the welded portions 28,28′ of the tubular web 30′ areflattened by the pressure applied by the flattening ultrasonic horn 33vibrating the tubular web 30′ over the cylindrical rotating anvil 34.The opposite top and bottom layers of the tubular web 30′ are not weldedtogether because the conditions of the process are controlled to avoid awelding operation. Exemplary weld flattening conditions are disclosed inthe process specification to follow.

[0060]FIG. 3F shows the reformed tubular web 30′ with the weldedportions 28,28′ out of alignment and substantially flattened. As shown,slight bulges 36,36′ remain in the tubular web 30′ at the weldedportions 28-28′.

[0061]FIGS. 4 and 4′ show a full production line for manufacturing theclosed reformed tubular web 30′ made of two continuous substrate sheets18,20 of differently appearing material. FIG. 4′ is a continuation ofthe line shown in FIG. 4. Narrow webs of the two continuous substratesheets 18,20 wound on driven supply reels 40′,42 are unwound by thepulling force of drive and nip rollers 35,37. The substrate sheets 18,20pass through a series of rollers designed to maintain tension in thesubstrate sheets 18,20. To this end, the substrate sheets 18,20 firstrespectively pass over idler rollers 44, and down under conventionaldancer tensioning rollers 46 which are mounted on arms (not shown) whichmove up and down to keep a constant tension in the continuous substratesheets 18,20. The tendency of these and other dancing rollers, to bedescribed, to move up and down is opposed by a feedback control systemwhich controls the driving speed of the supply reels 40,42 and take-upreel 128 upon which the completed web 30 is wound. The substrate sheets18,20 continue over second idler rollers 48. After the substrate sheets18,20 pass over idler rollers 48, the first substrate sheet 18 passesthrough a conventional photo-cell controlled edge guidance rollerassembly 50 which keeps the sheet in longitudinal alignment. Thesubstrate sheet 18 next passes under a third idler roller 52 and to apair of idler rollers 60-62. The roller assembly 50 includes a supportframe 50′ mounted for pivotal movement about a vertical axis andphoto-cells 50″ sensing the positions of the edges of the substratesheet 18. After passing over the second idler roller 48, the secondsubstrate sheet 20 passes under the third idler roller 52 and through aconventional photo-cell controlled edge guidance roller assembly 50,like the assembly 50 just described. The substrate sheet 20 then passesup to the pair of idler rollers 60,62. At the idler rollers 60,62, thesuperimposed substrate sheets 18,20 have their longitudinal margins oredges aligned.

[0062] The two superimposed substrate sheets 18,20 next pass throughadjustable longitudinally-spaced non-rotating shafts 54,56,58, which arevertically adjustable. The shafts 54,56 adjust the elevation of the twosuperimposed substrate sheets 18,20. The shaft 58 is positioned belowshafts 54,56 and is vertically adjustable to control tension in thesubstrate sheets 18,20 to eliminate any wrinkles at the weldingassembly. The first substrate sheet 18 passes over the shaft 54 andbetween the shafts 56 and 58. The second substrate sheet passes underthe shaft 54 and between the two shafts 56 and 58.

[0063] The superimposed substrate sheets 18,20 next pass between thecommon ultrasonic horn 26 and the rotating or stationery slit/weldanvils 24,24′, where the sheets' opposite longitudinal edges 22,22′ arewelded together, as previously described with respect to FIGS. 3B-3C.This, as noted before, forms a continuous tubular web 30 of differentlyappearing substrate sheets 18,20 superimposed and welded together in thehorizontal plane. The welding process carried out by the ultrasonic horn26 and rotating slit/weld anvils 24,24′ produce selvedge portions 32,32′at the longitudinal edges 22,22′ of the tubular web 30. The tubular web30 and selvedge portions 32,32′ then pass through a pair of slit sensorpins 59,59.

[0064] The pair of slit sensor pins 59,59 are further shown in FIGS. 4Aand 4B and extend upward from a common controlled shaft 59′. The sensorpins 59,59 pass between the selvedge portions 32,32′ and the weldedportions 28,28′ of the substrate sheet 18,20 before the same reaches therollers 35,37. The sensor pins 59,59 detect whether the slit/weld anvils24,24′ have completely slit through the substrate sheets 18,20 whichwould normally indicate that the slit/weld anvils 24,24′ are operatingproperly. The slit/weld anvils will wear over time and eventually failto completely slit through the substrate sheets 18,20. If this occurs,the portion of the substrate sheets 18,20 not slit engages the slitsensor pins 59,59, which will rotate the common controlled shaft 59′forward. As shown in FIG. 4B, this forward rotation of the shaft 59′ isconnected to a switch means 61 which shuts down the production line sothat the worn, defective slit-weld anvil can replaced.

[0065] The tubular web 30 and selvedge portions 32,32′ next pass betweena driven bottom roller 35 and a top nip roller 37, which pull thesubstrate sheets 18,20 through the welding assembly. The selvedgeportions are wound on take-up reel 64. The tubular web 30 then passesover an idler roller 63 which restores the elevation of the tubular web30 to the elevation occupied by the tubular web 30 at the weldingapparatus.

[0066] After the welding, but before the weld flattening operation, aspreviously described, web-reforming means are provided which transitionthe welded portions 28,28′ of the tubular web 30 from the outer edges ofthe tubular web 30 to positions on top and bottom of a flat reformedtubular web 30′, as shown in FIG. 3E. This transition of the weldedportions 28,28′ preferably takes place in the specific mannerillustrated in FIGS. 4C-4H.

[0067] The tubular web 30 lies in a horizontal plane after exiting theultrasonic horn 26 and slit/weld anvil 24,24′ assembly and is twistedinto a vertical plane by passing through one of the vertical slots 67formed between a first pair of spaced vertical rods 68,68 of a firstcomb-like structure 66 shown in FIGS. 4′ and 4C. The vertical,horizontally spaced rods 68 are mounted on a base 66 supported on a post67. The tubular web 30 then passes through a second comb-like structure66′ identical to the first comb-like structure 66. Using two comb-likestructures assures the tubular web 30 is kept in a vertical plane beforeit enters the next steps of the process; it also reduces stress on theweb 30.

[0068] The vertically oriented tubular web 30 is then expanded toreceive an insert structure 70 illustrated in greater detail in FIGS.4D-4G. As seen in FIG. 4D, the insert structure 70 floats within andkeeps the tubular web 30 open, with the welds 28,28′ at the top andbottom of the web 30. The tubular web 30 is then re-flattened in a planeslightly less than 90 degrees from the plane of the interfaces betweenthe substrate sheets 18,20 when they were originally welded together.FIG. 4E shows the insert structure 70 including a pair of horizontallyspaced vertical support plates 72,72′ between which are rotatablymounted two narrow, vertically spaced rollers 74,76 having outwardlytapering peripheral portions 74 a,76 a ending at peripheral flat crownportions 74 b,76 b. A horizontal, rearwardly tapering guidance plate 78is secured to the vertical support plates 72,72′ and extends forwardlytherefrom. The tapered guidance plate 78 rests on a stationary shaft 86for support. FIG. 4F illustrates in dashed lines a cross-section of thetubular web 30 passing around the insert structure 70, with the flatcrown portions 74 b,76 b of the roller peripheries engaging andexpanding the open web, so that the welded portions 28,28′ at the topand bottom of the vertically oriented tubular web 30 ride along the flatcrown portions 74 b,76 b.

[0069] To prevent the guidance plate 78 from shifting in a lateraldirection, a pair of rotatable plate-holding members 78′ are positionedon opposite sides of the guidance plate 78. The members 78′ rotate whilepressing against the outer sides of the web against the edge of theguidance plate 78 as shown in FIGS. 4′ and 4F.

[0070] The expanded web 30 is then kept expanded in a horizontal planeby the guidance plate 78 and in a vertical plane by the flat crownportions 74 b,76 b of rollers 74,76. A pair of fixed cylindrical outerguide members 77,79 are provided with tapered slotted portions 81 a,83 awhich closely but in spaced relation confront the forwardly facing sidesof the rollers 74,76 respectively at the upper and lower marginsthereof. The outer guide members 77,79 are formed by a pair of bearings77 a-b, 79 a-b with tapered confronting surfaces 77 a′-b′ and 79 a′-b′which are spaced apart by O-rings 81,83 and define grooves 81 a,83 awith the tapered surfaces 77 a′-b, 79 a′-b′ closely confronting the flatcrown portions 74 a-b,76 a-b of the rollers 74,76 of the insertstructure 70. The forward movement of the expanded web 30 pushes theinsert structure 70 forward towards the outer guide members 77,79 sothat the expanded web 30 is forced between the outer guide members 77,79and the vertically spaced rollers 74,76. FIG. 4G is a view of the topportion of FIG. 4E. It shows the welded portion 28 riding along the flatcrown portion 76 b as the web 30 passes between the roller 76 and outerguide member 77.

[0071] As seen in FIGS. 4′ and 4H, after tubular web 30 passes aroundthe insert structure 70, the web 30 passes between a stationary groovedsleeve 86′ and a stationery grooved sleeve 87′. The insert structureguide plate 78 rests on the stationary shaft 86. The sleeves 86′,87′ aresecured by one or more set screws 86″,87″ to stationary shafts 86,87.The shaft 87 is vertically adjustable and is located slightly downstreamand above the shaft 86. As best seen in FIG. 4H, the sleeves 86′,87′have laterally offset grooves 88,89 into which the bulging weldedportions 28,28′ of the web 30 enter respectively, to laterally offsetthe welded portions 28,28′. This lateral offset reduces the thickness ofthe completed cellular panel 10 when in a collapsed configurationbecause the welded portions 28,28′ slightly bulge the tubular web 30.The grooved sleeves 86′,87′ are positioned by set screws 86″ and 87″ toobtain the desired offset positions. The stationary shafts 86,87 maycarry additional grooved sleeves if manufacturing a plurality of webs atthe same time, as seen in FIGS. 4M and 4N.

[0072] The web 30, after leaving the grooved sleeves 86′,87′, enters theweld flattening assembly comprising the flattening ultrasonic horn 33and cylindrical rotating anvil 34 shown in FIG. 3E. The top and bottomwelds 28,28′ are located to the right and left of center lines of thetop and bottom walls of the reformed web 30′, as shown in FIG. 3E. Thereformed tubular web 30′ passes between the flattening ultrasonic horn33 and cylindrical rotating anvil 34 shown in FIG. 3E which flattens theprojecting weld 28,28′ of the reformed tubular web 30′ to produce a webof similar thickness throughout.

[0073] As shown in FIGS. 4′ and 4I, the reformed web 30′ passes betweenanother ultrasonic horn 92 and a cylindrical rotating anvil 94 similarto the weld flattening assembly previously described. This secondultrasonic horn 92 vibrates the reformed web 30′ against the secondcylindrical rotating anvil 94 to set the folds made at the outerlongitudinal edges of the reformed web 30′. As best seen in FIG. 4I, thesecond cylindrical rotating anvil 94 has a recessed portion 96substantially at its center where the welded portions 28,28′ passthrough. Without the recessed portion 96, the bulging welded portions ofthe web 30′ would become heated to a much higher temperature than therest of the web, which could cause a possible undesired welding togetherof the overlying layers of the web. This prevents the second ultrasonichorn from working directly onto the welded portions 28-28′ andconcentrates the work performed on the longitudinal edges of thereformed web 30′.

[0074] After this foldsetting, the reformed web 30′ passes between driveroller 110 and nip roller 112 (FIG. 4′). The nip roller 112 is a biascontrolled roller. The nip roller 112 is, thus, adjustable allowing thenip roller 112 to apply more pressure to one side of the reformed web30′ than the web's other side. Such a roller improves the control overthe path of the web. The thicknesses of the substrate sheets 18,20forming the web 30′ can be different. Due to this possible variation inthickness, the web may try to move laterally as it passes between thedrive and the nip rollers 110,112. The bias control nip roller 112prevents any lateral movement of the web 30′ and assures the web 30′travels in a straight path.

[0075]FIGS. 4K and 4L illustrate the bias control nip roller 112 in moredetail. FIG. 4K is a side view of the nip roller 112 taken along theline 4K-4K in FIG. 4J. FIG. 4L is a cross-sectional view taken along theline 4L-4L in FIG. 4K. The nip roller 112 has a grooved sleeve 130 whichrides about a plurality of bearings 131 adjacent a common shaft 132. Thegrooved sleeve has outer sections 133,134 which contact the reformed web30′. The grooved sleeve 130 allows the welded portions 28,28′ to passwithout contacting the nip roller 112. Spring assemblies 135,136,located on each end of the shaft 132, apply pressure independently toeach outer section 133,134 of the nip roller 112. Set screws 137,138allow the pressure to be adjusted on each outer section 133,134 of thenip roller 112. As described before, more pressure can then be appliedto one side of the reformed web 30′ than the other to prevent anylateral movement of the web 30′ due to the different thicknesses of thesubstrate sheets 18,20.

[0076] The web 30′ is next pulled under tension over a heated upwardlyhoned or cambered plate 106, as shown in FIG. 4′ and FIG. 4J, to relievethe stresses produced in the flattened welded portions 28,28′ of thereformed tubular web 30′. The cambered plate 106 is heated by a heatingelement 108 positioned below the plate. The tubular web 30′ is forceddownward against the heated cambered plate 106 by the passage of the web30′ between drive and nip rollers 110,112, the nip roller 112 beingpositioned below the lower inlet end of plate 106 and then between driveand nip rollers 116,114 at the outlet end of the plate 106 as seen inFIG. 4′ and FIG. 4J.

[0077] Nip roller 114 is also a bias control roller, identical to niproller 112, to assure the web passes over the upwardly honed camberedplate 116 in a straight path.

[0078] Heating the reformed tubular web 30′ under tension relievesstresses produced in the welded portions 28,28′ of the tubular web bythe welding process. These stresses are apparent by a longitudinal bowin the reformed tubular web 30′ and ripples at the welds 28,28′ prior topassing over the heated cambered plate 106. The relief of these stressesin the welds 28,28′ minimizes any ripples and produces a flat, unbowedtubular web 30′.

[0079] As seen in FIG. 4′, the reformed tubular web 30′ passes under afurther idler roller 118, over an adjacent idler roller 120 and passesunder a dancer tensioning roller 122 which controls tension in the web30′. The web 30′ proceeds over the two idler rollers 124,126 to anindividual powered take-up reel 128 for later fabrication, as shown inFIG. 4, or is immediately processed to form the cellular panel 10.

[0080] Although FIGS. 4A-4L show the manufacture of only one tubular web30 at a time, the comb-like structure 66 (FIG. 4N) has a plurality ofvertical rods 68 to receive a number of tubular webs 30 a-30 dsimultaneously. Such a modified production line is shown in FIG. 4M. Asseen in FIG. 4M, a number of tubular webs 30 a-30 d can be manufacturedfrom a wider, continuous tubular web of a pair of supplementalcontinuous substrate sheets 18 a,20 a. The continuous substrate sheets18 a,20 a, made of similar material as substrate sheets 18,20, areunwound from powered supply reels (not shown) and pass through a similarset of rollers (like rollers 44 through 60), as shown in FIG. 4. Theserollers are wider, however, to accommodate the wider substrate sheets 18a,20 a. The superimposed wider substrate sheets 18 a,20 a then arepassed between a common ultrasonic horn 26′ vibrating the widersuperimposed substrate sheets 18 a,20 a against a plurality of laterallyspaced rotating slit/weld anvils 24′ positioned adjacent to one another.This produces a plurality of closed welded tubular webs 30 a-30 d whichpass through a plurality of slit sensor pins 59 (as described before).The webs 30 a-30 d pass between the vertical rods 68 in the comb-likestructures 66,66′ (FIG. 4N) Each tubular web 30 a-30 d is then furtherprocessed in the manner just described and wound onto separate reels.

[0081] Exemplary specifications for some of the production linesdescribed include a sonic horn like that shown in FIG. 4P. The sonichorn is connected to a booster B1 driven by a converter C1 which is fedfrom a commercial AC power line.

[0082] The following are a set of exemplary specifications for theproduction line shown in FIGS. 4 and 4′:

[0083] 1. Web feed speed: 17.5 feet per minute

[0084] 2. Specification of substrate sheet 18: 0.007″ thick wovenpolyester fabric.

[0085] 3. Specification of substrate sheet 20: 0.007″ thick non-wovenpolyester fabric.

[0086] 4. Specification of sonic welder ultrasonic horn 26:

[0087] a. power supply; converts 50/60 Hz line current to 20 KHzelectrical energy;

[0088] b. converter; converts electrical oscillations into mechanicalvibrations.

[0089] c. booster (1:2 ratio); modifies the amplitude of vibrations.

[0090] d. amplitude (65% setting at power supply control); function ofhorn shape, peak to peak displacement of the horn at its work face.

[0091] e. horn; ½″×9″ carbide tipped face titanium.

[0092] f. manufactured by Branson Ultrasonics Corporation, 41 EagleRoad, Danbury, Conn. 06813 identified by Model Number 900B.

[0093] 5. Specification of slit/weld anvil 24: stationary, 1″ diameter,⅛″ wide, 150 degrees, 0.005 r.

[0094] 6. Slit/weld anvil 24 pressure against web: 40 PSI.

[0095] 7. Specification of weld-flattening ultrasonic horn 33:

[0096] a. power supply; converts 50/60 Hz line current to 20 KHzelectrical energy;

[0097] b. converter; converts electrical oscillations into mechanicalvibrations.

[0098] c. booster (1:1.5 ratio); modifies the amplitude of vibrations.

[0099] d. amplitude (80% setting, pneumatic engagement and retraction.

[0100] e. horn; ½″×9″ carbide tipped face titanium.

[0101] f. manufactured by Branson Ultrasonics corporation, 41 EagleRoad, Danbury, Conn. 06813 identified by Model Number 900AO.

[0102] 8. Specification of weld-flattening cylindrical anvil 34: 4″diameter, driven at 17.85 feet per minute (2% overdrive for webtensioning).

[0103] 9. Specification of grooved guide rollers 77,79: ⅞″ diameter,{fraction (1/16)}″ spacing (o-ring), 1⅞″ vertical distance between upperand lower pairs.

[0104] 10. Specification of guide plate 78: 0.030″ thick, {fraction(9/16)}″ to 1{fraction (5/16)}″ taper over 9½″ distance.

[0105] 11. Specification of foldsetting ultrasonic horn 92:

[0106] a. power supply; converts 50/60 Hz line current to 20 KHzelectrical energy;

[0107] b. converter; converts electrical oscillations into mechanicalvibrations.

[0108] c. booster (1:1.5 ratio); modifies the amplitude of vibrations.

[0109] d. amplitude (80% setting, pneumatic engagement and retraction.

[0110] e. horn; ½″×9″ carbide tipped face titanium.

[0111] f. manufactured by Branson Ultrasonics Corporation, 41 EagleRoad, Danbury, Conn. 06813, identified by Model Number 900AO.

[0112] 12. Specification of foldsetting cylindrical anvil 94: 4″diameter, driven at 17.85 feet per minute (2% overdrive for webtensioning) with weld seam clearance relief.

[0113] 13. Pneumatic pressure exerted by weld-flattening ultrasonic horn33 against weld-flattening cylindrical anvil 34: 12-14 PSI.

[0114] 14. Pneumatic pressure exerted by foldsetting ultrasonic horn 92against foldsetting cylindrical anvil 94: 22-24 PSI.

[0115] 15. Specification of nip rollers 112,114: 1⅛″ wide, 2″ diameter,¼″ wide groove.

[0116] 16. Specification of heated cambered plate 106: 230 degrees F.,½″ rise at center 24″ length.

[0117] 17. Specification of drive roller peripheral speed: 17.94 feetper minute (0.5% tensioning overdrive).

[0118]FIG. 5 is a block diagram illustrating the steps of forming acellular panel 10, from a continuous flat reformed tubular web like web30′,30 a,30 b,30 c or 30 d. The functions performed by the blocks showntherein may be performed, for example, by the tension control webaligning, adhesive applying, and web cutting and stacking chamberdisclosed in U.S. Pat. No. 4,450,027 or copending application Ser. No.07/839,600 filed Feb. 28, 1992. A pair of reels of a pair of reformedwebs 30 a′ and 30 b′ are shown in FIG. 5 supported one above the other.The web 30 a′ on one reel is unwound in a horizontal plane while itpasses first through tension control and web aligning means 41comprising rollers (not shown) to maintain tension and laterally alignthe tubular web 30 a′. The tubular web 30 a′ then passes through anadhesive applying means 43 which applies the two bands 11,11′ ofadhesive, (FIG. 1). The two bands of adhesive 11,11′ are applied to theportion of the web 30 a′ to form the top wall portion 15 of each cell 12formed from the tubular web 30 a, (FIG. 2). As shown in FIG. 1A, thebands of adhesive 11,11′ are applied over the welded portions 28,28′ ofthe tubular web 30 a′ to reinforce the welds. The bands of adhesive11,11′ are spaced to leave the center portion of the top wall portion 15of the tubular web 30 a′ free of adhesive. This allows for drillingthrough the center of the top wall portion 15 of the tubular web 30′ toaccommodate the drawstrings of a complete cellular panel 10 without thedrilling means coming into contact with the adhesive. If adhesive wasapplied along the entire top wall portion 15, the drilling means wouldhave to be periodically cleaned or replaced after the adhesive built upon the drilling means.

[0119] Referring again to FIG. 5, the tubular web 30 a′ is then cut intoidentical tubular strips by a cutting means 45. The strips cut from theweb 30 a′ form the cells or tubular sections 12 of the panel 10. The web30 a′ is then fed by high speed conveyor means 47 to a stacking chamber49, both similar to that disclosed in U.S. application Ser. No. 839,600.The stacking chamber 49 receives the flat tubular strips through a strippass-through slot (not shown) located in the floor of the stackingchamber extending the length of the tubular strips. The conveyor means47 includes a stationary conveyor belt section 47 a which separates thecut strips and a raisable conveyor section 47 b which is raised by alifter means 51. The conveyor sections 47 a,47 b may each includesuction conveyor belts which hold the strips by suction thereon. Thelifter means 51 raises the raisable conveyor 47 b through the slot inthe floor of the stacking chamber 49. This pushes the strip, held on thebelts by suction, off the belts and up against the strip above it. Thisstrip is thus raised in the stacking chamber 49, so that the adhesivebands 11,11′ adhere to the bottom of the strip above it, as shown inFIG. 1A. The movement of the belt forming the raisable conveyor 47 b isstopped when a strip is in alignment along its length with the inletslot of the stacking chamber 49.

[0120] To properly align the tubular strips in the stacking chamber 49,the bottom of the stacking chamber may be defined by a pair of verticalconfronting walls (not shown) which are spaced apart a distance slightlygreater than the width of the strips. These walls thus laterally aligneach strip being pushed into the stacking chamber with the strip aboveit. The upper portion of the stacking chamber preferably has oppositeupwardly diverging walls so that the laminated strips raised momentarilyin the chamber will not get stuck in the chamber. The proper timing ofthe operation of all of the stations of the production line shown inFIG. 5 is determined by suitable and conventional control meansidentified by a block 53 in FIG. 5.

[0121] After a strip is pushed into the stacking chamber and adhered tothe strip above it, the lifter means 51 lowers the raisable conveyor 47b which passes down through the pass-through slot in the bottom of thestacking chamber 49. The strip just stacked separates from the raisableconveyor as it is pulled against the floor of the chamber 49 by thedownward movement of the raisable conveyor 47 b. The movement of thebelt of the raisable conveyor 47 b then resumes as it receives the nextstrip to be pushed into the stacking chamber 49. The sequence ofoperation just described is repeated to form the expandable cellularpanel 10 in a mass production operation. When one of the web reels 30 a′is completely unwound, a photo cell (not shown) senses this conditionand stops the web feed. The leading edge of the other reel, for webmaterial 30 b′, is then spliced to the trailing edge of the completelyunwound web 30 a′.

Embodiment of FIGS. 6-10

[0122] FIGS. 6-10 illustrate another embodiment of the present inventionwhere a non-light controlling cellular panel 10′ is made similar to thepanel 10 shown in FIG. 1, except that it is formed from a plurality ofhorizontally elongated open top tubular sections 12′ or cells ratherthan closed tubular sections. FIG. 6 shows a portion of such a cellularpanel 10′. As seen in FIG. 7, each tubular section 12′ is formed offront and rear substrate sheets 18′,20′ of two differently appearingsubstrate materials. Each tubular section 12′ has a top wall portion15′, formed by spaced inturned longitudinal margins of the substratesheets 18′ and 20′, a bottom wall portion 17′ formed by the oppositelongitudinal margins of the substrate sheets welded together at 28 a,and front and rear wall portions 14′ and 16′ respectively formed by thesheets 18′ and 20′. Each tubular section 12′ is formed from strips cutfrom a folded continuous two-substrate web formed by folding theinitially flat web 31, (FIG. 8F). The outer longitudinal marginalportions of the unfolded continuous multi-substrate web 31 are foldedover the central portion of the web to form an open tubular flat webwhich is coated with adhesive, cut into strips, and the adhesive-coatedstrips are sequentially stacked. The flat web 31 is made in the mannershown in FIGS. 8A-F.

[0123]FIG. 8A shows two differently appearing substrate sheets 18′,20′with their opposite longitudinal edges 22,22′ aligned. FIG. 8B shows thesubstrate sheets 18′,20′ superimposed with only one of their alignedlongitudinal edges 22,22′ being welded together at 28 a. The substratesheets 18′,20′ pass between a preferably driven rotating slit/weld anvil24 and an ultrasonic horn 26. This assembly is similar to that used inthe welding process described with respect to the closed tubular web 30in FIGS. 1-5. The ultrasonic horn 26 vibrates against the rotatingslit/weld anvil 24, welding the substrate sheets 18′,20′ together toform a continuous folded tubular web 31 open at one end. This processproduces a selvedge portion 32′ which is collected. The web is thenunfolded to form the flat web 31 shown in FIG. 8D and the weld 28 a isflattened by a flattening ultrasonic horn 33 pressing the downwardlyprojecting weld against a cylindrical driven rotating anvil 34, as shownin FIG. 8E. The cylindrical rotating anvil 34 is driven. The weldflattening process just described leaves just a slight bulge 36 in theopen multi-substrate web 31.

[0124]FIG. 9 illustrates a portion of the production line utilized inmanufacturing the open tubular web 31. The production line has twopowered supply reels 40′,42′ of the substrate sheets 18′,20′ made ofdifferent material. The substrate sheets 18′,20′ pass through anidentical roller set up (not completely shown) as previously discussedfor the closed tubular web 30 which tensions the substrate sheets18′,20′ and superimposes the opposite longitudinal edges 22,22′ of thesubstrate sheets 18′,20′.

[0125] The substrate sheets 18′,20′ are then welded together at one oftheir aligned longitudinal edges 22,22′ by the vibrating ultrasonic horn26 and slit/weld anvil 24 assembly, as previously described with respectto FIG. 8B. The selvedge portion 32′ produced by the welding process isalso wound upon a driven take-up reel 64. After the substrate sheets18′,20′ are welded together, a continuous open tubular web 31 is formedhaving different appearing substrate materials. The open tubular webthen passes between drive roller 35 and nip roller 37 which pull thesubstrate sheets 18′,20′ through the welding assembly 24,26. Althoughnot shown in FIG. 9, it is understood that the open tubular web 31 canalso pass through slit sensor pins as described.

[0126] The open tubular web 31 is then unfolded prior to entering theweld flattening assembly to form an unfolded flat multi-substrate web.To aid in unfolding the open tubular web 31, the open tubular web 31passes under a skewed roller assembly 75 made up of skewed top drivenrollers 75 a,75 a which exert outward forces on the web 31 and a drivenbottom roller 75 b. The unfolded multi-substrate web 31 then passesbetween two idler rollers 81,83, and under a dancer tensioning roller85, which controls tension in the web 31 by adjusting the speed of thedriven supply and take-up reels 40′,47′,128. The web proceeds over afurther idler roller 87 before entering the weld flattening apparatus.The welded portion 28 a of the open multi-substrate web 31 is thenflattened by the flattening ultrasonic horn 33 and cylindrical rotatinganvil 34, as previously described with respect to FIGS. 8C-8E.

[0127] After the flattening process, the flat open multi-substrate web31 passes between drive and nip rollers 110,112 and over a heatedcambered plate 106 to relieve the stresses produced in the weldedportion 28 a of the open multi-substrate web 31 from the welding processas seen in FIG. 9. The heated cambered plate 106 is identical to thatdescribed in the embodiment for the closed tubular web 30 with respectto FIGS. 1-5. The heat subjected to the open multi-substrate web 31relieves the stresses in the welded portion 28 a, thus minimizingripples and producing a flat, as well as straight open multi-substrateweb 31, which then can be processed further with less difficulties.

[0128] The open multi-substrate web 31 continues between drive and niprollers 114,116, and under a dancer tensioning roller 119, whichcontrols tension in the web 31. The web 31 proceeds over an idler roller121 to an individual powered take-up reel 128 for later fabrication asshown in FIG. 9, or is immediately processed to form the cellular panel10′.

[0129]FIG. 10 is a block diagram illustrating the steps in forming theopen cellular panel 10′ of FIG. 6 formed from the flat web 31. It isvery similar to the process for making the cellular panel 10 formed bythe closed tubular web 30 as previously discussed with respect to FIGS.1-5. Accordingly, similar stations in FIG. 10 have been identicallynumbered to those in FIG. 6. One difference is the addition of foldingmeans 55 before the adhesive applying means 43. A suitable folding meansis disclosed in U.S. Pat. No. 4,450,027 or in U.S. application Ser. No.08/040,869, filed on Mar. 31, 1993, entitled “Folding Plate Assembly ForFabricating Honeycomb Insulating Material” and filed in the names ofBryan K. Ruggles and Cary L. Ruggles. As disclosed in that application,the folding means includes a slot folding plate assembly through whichthe web 31 passes. The slot is shaped to cause the outer longitudinaledges of the flat multi-substrate web 31 to raise above and over thecentral portion of the web 31, thus folding the web. The confrontinglongitudinal margins of the folded web which form the top wall portion15′ of the folded web do not contact one another, leaving a gap 57 inthe top wall portion 15′ (FIG. 6A). The folding means 55 may alsoinclude a fold setting means in the form of a heated drum (not shown)which heats the web material to its heat set temperature. The heatedfolded web is pressed against the drum to form sharp permanently setfolds. A cooling means (not shown) then cools the pressed web below thesetting temperature forming set pressed folds 13,13′ shown in FIGS. 6and 7.

[0130] The tubular web 31 next passes through adhesive applying means 43which applies two bands of adhesive 11-11′ on the top wall portion 15′of the open tubular web 31 (FIG. 7). The open tubular web 31 is then cutinto identical tubular strips by cutting means 45 which, by conveyermeans, are fed to a stacking chamber 49 which may be similar to thatdisclosed in U.S. application Ser. No. 07/839,600, as previouslydiscussed in detail with respect to the closed tube cellular panel 10 ofFIGS. 1-5.

Embodiment of FIGS. 11-14

[0131] FIGS. 11-14 illustrate a light controlling cellular panel 10″ ofthe present invention. It comprises horizontally elongated verticallyaligned cells or tubular sections 12″ formed from an open flat tubularweb 30″. The web 30″ is folded, coated with adhesive, and cut intostrips; the strips are then stacked in the manner previously described.An opaque substrate sheet 19″ in each tubular section 12″ controls lightpassing through the panel 10″. When the opaque substrate sheet 19″ isrotated to a vertical plane, light passing through the panel isobstructed.

[0132]FIG. 11 shows a portion of the light-controlling cellular panel10″. The cellular panel 10″ is formed by laminating separate opentubular strips when in a flattened condition, as shown in FIGS. 14C and14D, to form a tubular section 12″. Each cell 12″ has a front wallportion 14″ made of a sheer substrate sheet 18″ of one mesh size, a rearwall portion 16″ made of a sheer substrate sheet 20″ of a different meshsize, a bottom wall portion 17″ made of a wider substrate sheet 19″ ofopaque material, and a top wall portion 15″ which is formed by thebottom wall portion 17″ of an adjacent call 12″ and the inwardly turnedupper ends of the substrate sheets 18″,20″ secured to the opaque sheet19″ by spaced bands of adhesive 11″.

[0133] The open tubular strips are first formed from a flat continuousweb 30″ made of three separate substrate sheets 18″,19″,20″ (FIG. 12A)which are welded together along their longitudinal margins. FIG. 12Ashows the three superimposed substrate sheets 18″,19″,20″ with the leftlongitudinal edges 22′ and 22″ of the wider central opaque substratesheet 19″ and lower sheer substrate sheet 20″ aligned, and the rightlongitudinal edges 22″ and 22 of the central opaque substrate sheets 19″and upper sheer substrate sheet 18″ aligned. As seen in FIG. 12B, thethree-substrate sheets 18″,19″,20″ are welded together at their alignedtwo-substrate thick longitudinal edges by passing the substrate sheets18″,19″,20″ between a common vibrating ultrasonic horn 26 and slit/weldanvils 24 identical to the welding apparatus as previously described.Thus, outer sheer substrate sheet 18″ is welded to the wider opaquesubstrate sheet 19″ at the right aligned longitudinal edges thereofwhile the other outer sheer substrate sheet 20″ is simultaneously weldedto the opaque substrate sheet 19″ at the aligned left longitudinal edgesthereof to form a Z-shaped web 30″ which is unfolded, as shown in FIG.12C. When unfolded, the web 30″ has a center opaque substrate sheet 19″and outer sheer substrate sheets 18″,20″ all in the same plane.

[0134] After the welding process, the welded portions 28″ of theunfolded web 30″ are flattened to form a flat web of similar thicknessthroughout. As seen in FIG. 12D, the welded portions 28″ are flattenedby passing the flat multi-substrate web 30″ between the flatteningultrasonic horn 33 and cylindrical rotating anvil 34. The pressureapplied by the flattening ultrasonic horn 33 to the welded portions 28″of the multi-substrate web 30″ against the cylindrical rotating anvil 34flattens the welded portions 28″ to produce a multi-substrate web 30″with similar thickness throughout.

[0135]FIG. 13 shows a portion of the production line for manufacturingthe continuous flat multi-substrate web 30″. The production line beginswith driven reels 40″,41″ and 42″ of continuous substrate sheets 18″,19″and 20″ unwinding the sheet material therefrom. The substrate sheets18″,19″,20″ pass through similar sets of web-tensioning rollers (notshown) as discussed previously. The three-substrate sheets 18″,19″,20″are then superimposed with their longitudinal edges aligned asdescribed, by passing them in superimposed relation between a pair ofidler rollers 60″,62″ with one outer sheer substrate sheet 18″ on top,the center opaque substrate sheet 19″ in the middle, and the outer sheersubstrate 20″ on the bottom of the superimposed stack of sheets.

[0136] Each outer sheer substrate sheet 18″,20″ is then simultaneouslywelded to the longitudinal edge of the center opaque substrate sheet 19″in alignment therewith by vibrating ultrasonic horn 26 and against theslit/weld anvils 24, as previously described with respect to FIG. 12B.The selvedge portions 32″ produced by the welding process are alsorewound by take-up reels 64″. After the substrate sheets 18″,19″,20″ arewelded together, a Z-shaped web 30″ as formed. The Z-shaped web passesbetween a drive roller 35″ and a nip roller 37″ which act to pull thesubstrate sheets 18″,19″,20″ through the welding assembly. Although notshown in FIG. 13, it is understood that the web 30″ can also passthrough slit sensor pins as previously described with respect to theclosed-tube cellular panel 10.

[0137] As previously described, the Z-shaped web 30″ is then unfoldedbefore entering the weld flattening apparatus to form a flat substratesheet. To aid in the unfolding, the Z-shaped web 30″ passes beneath askewed roller assembly 75″ comprised of driven upper rollers 75 a″,75b″,75 c″ and bottom roller 76 d. The driven rollers 75 a″ and 75 c″overlying the outer sheet substrate sheets 18″, 20″, exert downward andoutward forces on the outer sheer substrate sheets 18″ and 20″. Atransversely extending roller 75 b″ overlying the central opaque sheet19″ exerts a downward force on the center opaque substrate sheet 19″passing beneath the same. The flat multi-substrate web 30″ then passesover an idler roller 83″, under a dancer tensioning roller 85″ and overa second idler roller 87″. The projecting welded portions 28″ of themulti-substrate web 30″ are then flattened by the flattening ultrasonichorn 33 and cylindrical rotating anvil 34, as previously described withrespect to FIG. 12D.

[0138] After the flattening process, the flattened multi-substrate web30″ passes between drive and nip rollers 110″,112″ and then over aheated cambered plate 106 to relieve the stresses produced in the weldedportions 28″ of the multi-substrate web 30″ from the welding process.The heated cambered plate 106 is identical to that described in theembodiments of FIGS. 1-5.

[0139] The multi-substrate web 30″ then continues between further driveand nip rollers 114″,116″, under a dancer tensioning roller 118″ andover an idler roller 120″ to either an individual driven take-up reel128″ for later fabrication as shown in FIG. 13, or immediately processedto form the cellular panel 10″.

[0140]FIG. 14 shows a block diagram illustrating the steps of formingthe light controlling cellular panel 10″ formed from the flat unfoldedmulti-substrate web 30″. It is very similar to the process utilized tomake cellular panel 10′ formed from an open tubular web in accordancewith FIG. 10. Accordingly, corresponding reference numerals are used inFIG. 14 to avoid a repetition of description. However, the folding means55′ is different from the folding means 55 in FIG. 10 which forms sharpset folds 13′-13′ in the web 31′. The folding means 55′ includes noheated drum or other means to set any folds so that, as shown in FIG.11, there are no folds seen at the sides of the rectangular tubularsections. The folding means, therefore, preferably includes only a slotforming plate, as shown in copending application Ser. No. 839,600.

[0141] FIGS. 14A-14D illustrate respectively transverse sections of theweb 30″ as it unwinds from the reel 128″, and when it leaves the foldingmeans 55′ and adhesive applying means 43. Note that in FIG. 14C thebands of adhesive 11″-11″ deposited by the adhesive applying means 43 onthe folded-over marginal portions of the outer substrate sheets 18″ and20″ overlie the outer marginal portions of the opaque substrate sheet19″. FIG. 14D shows adjacent strips S1 and S2 cut from the web 30″pushed in the stacking chamber 49 where these strips are laminatedtogether by the adhesive bands 11″-11″. Thus, when a panel 10″, shown inFIG. 11, is allowed to expand, the calls or tubular sections have therectangular shape shown therein.

[0142] When the outer sheer substrate sheets 18″,20″, which form thefront or rear wall portions 14″ or 16″ of the cellular panel 10″, areshifted up or down with respect to each other, the wide opaque substratesheets 19″ of the various laminated strips shift from a horizontalposition where light passes through the cellular panel 10″. The opaquesubstrate sheets 19″ are then inclined upwardly to an upstandingposition where the opaque substrate sheets 19″ of adjacent stripsoverlap, because they are wider than the outer substrate sheets 18″,20″.In this position, the passage of light through the panel 10″ isprevented.

Embodiment of FIGS. 15-19

[0143] Another method of making a light controlling cellular panelcomprising of horizontally elongated vertically aligned cells utilizesan unfolded substrate web 30″ identical to that formed by the productionline shown in FIG. 13. However, the web 30″ is processed differently, asillustrated in FIGS. 16-19, to produce a panel 10′″ shown in FIG. 15which shows a portion of the panel 10′″. FIG. 16 shows themulti-substrate web 30″ with bands of adhesive B and B′ applied alongthe outer longitudinal margin, or the front sheer substrate sheet 18″,and along the rear margin of the opaque sheet 19″ opposite the inner orfront margin of the sheer substrate sheet 20″. The web 30″ is then cutinto strips sequentially to form three-substrate strips S1,S2,S3, etc.as shown in FIG. 17.

[0144] The closed tube cellular panel 10′″ is formed by laminating insequence the flat unfolded multi-substrate strips S1,S2, etc. togetherin identically oriented positions at transversely spaced pointstherealong to the previously cut strip located above it.

[0145] As shown in FIGS. 16 and 17, the bands of adhesive B,B′ of eachstrip thus adhere (a) the rear margin 127 of the center opaque substratesheet 19″ of each strip to the outer margin 130 of the rear sheersubstrate sheet 18″ of the strip above it, and (b) the outer margin 129of the front sheer substrate sheet 20″ of the former strip to the frontmargin 131 of the center opaque substrate sheet 19″ above it. FIGS. 15Aand 15B are fragmentary views of the portion of the cellular panel 10′″of FIG. 15, showing the adhesive connections of the identicalmulti-substrate strips when the panel is expanded. When the outer margin129 of the front sheer substrate sheet 18″ of the uppermost strip S1 andthe rear margin 127 of the center opaque substrate sheet 19″ of theuppermost strip S1 are fixed in the position they are to assume in theexpanded cellular panel 10′″, and the rest of the panel 10′″ is allowedto drop under the force of gravity, a light controlling panel 10′″ isformed comprising horizontally elongated vertically aligned closedtubular cells 12′″ as seen in FIG. 15. The front vertical wall 14′″ orside of each cell 12′″ is formed by the front sheer substrate sheet 18″of one of the multi-substrate strips; the rear vertical wall 16′″ orside of the cell 12′″ is formed by the rear sheer substrate sheet 20″ ofthe multi-substrate strip above it. The bottom horizontal wall 17′″ ofeach cell 12′″ is formed by the center opaque substrate sheet 19″ ofsaid one strip; and the top horizontal wall 15′″ of that cell is formedby the center opaque substrate sheet 19′″ of the strip above it. Statedanother way, the front and rear substrate sheets 18″,20″ of each stripform respectively the front and rear wall portions of adjacent cells.

[0146] In order to better understand the relationship between thevarious cut and laterally offset laminated multi-substrate stripsS1,S2,S3,S4 shown in FIG. 17 that form the expanded panel 10′″ in FIG.15, the front substrate sheet of each strip is designated by the letterF, the center opaque substrate sheet of each strip is designated by theletter C and the rear substrate sheet of each strip is designated by theletter R, with the particular substrate sheet of a given strip beingfurther identified by a reference number corresponding to the referencenumber identifying that strip. Similarly, the forwardmost adhesive bandof each strip is identified by the letter B and the rearmost adhesiveband of each strip identified by the letter B′, with the variousadhesive bands of the various strips each identified by a numbercorresponding to the number of the particular strip involved. Thus, thevarious substrate sheets, adhesive bands of the various strips shown inFIG. 17 can immediately be identified in FIG. 15.

[0147] The adjustment of the panel 10′″ to obtain the light passing andobstructing modes of operation is very similar to that of the open tubepanel 10″ of FIGS. 11-14. When the front and rear sheer substrate sheets18″,20″ of the multi-substrate strips S1,S2, etc. making up panel 10′″are shifted vertically relative to one another from their positionsshown in FIG. 15, the center opaque substrate sheets 19″ of the variousstrips of the cellular panel 10′″ are pivoted from horizontallight-passing positions to upstanding light-blocking positions. Becausethe center opaque substrate sheets 19″ are wider than the outer sheersubstrate sheets 18″,20″, the center opaque substrate sheets 19″ overlapone another in their light-blocking upstanding positions, thuspreventing any light from passing through the cellular panel 10′″.

[0148]FIG. 18 is a block diagram showing the different steps ofmanufacturing the cellular panel 10′″ of FIG. 15. The laminatedmulti-substrate strips forming a web 30″ are unwound from a drivensupply reel 128″ and pass through tension control and web aligning means41′. Adhesive bands B and B′ are applied by adhesive applying means 43′to the multi-substrate web 30″ and then the web 30″ is cut by cuttingmeans 45 into strips S1,S2,S3, etc. The multi-substrate strips are thencarried by high speed conveyor means 47, like that previously describedto the raisable conveyer portion 47 b. When the first strip S1 islaminated, the lifter means 51′ raises the raisable conveyor portion towhere the first strip S1 is laminated against a leader strip (not shown)carried by an overhead laterally indexable conveyor belt. After thefirst strip S1 is laminated, the second strip S2 is laminated to thefirst strip in the pattern described with respect to FIG. 17, and theprocess continues with the third strip S3, etc. The control means 53′control the operating sequence of the stations of the production linejust described.

[0149]FIG. 19 shows part of the manufacturing apparatus for making thelight controlling closed tube cellular panel 10′″ of FIG. 15. After themulti-substrate web 30″ is cut into strips S1,S2,S3, etc., adhesivebands B and B′ are applied at the proper longitudinal margins aspreviously described. A conveyor belt 150, represented by the stationaryconveyor block 47 a in FIG. 18, receives the multi-substrate strips S1,S2, etc. The conveyor belt 150 is provided with suction holescommunicating with a vacuum source (not show) to hold the stripsthereon. The conveyor belt 150 conveys the strips to the raisableconveyor belt 151, represented by block 47 b in FIG. 18. The raisableconveyor belt 151 also has suction holes 156 to allow a vacuum box 154,shown in FIG. 19, to hold the multi-substrate strips in place. To beginforming the cellular panel 10′″, the first multi-substrate strip islaminated to a leader strip located on a laterally indexable conveyorbelt 160. When the first multi-substrate strip S1 is then properlypositioned, the raisable conveyor 151 delivers the strip S1 to theoverhead laterally indexable conveyor belt 160, represented by block 49′in FIG. 18.

[0150] The laterally indexable conveyor belt 160 also has suction holes151′ communicating with a vacuum box 164 to hold in place the firstmulti-substrate strip S1 adhered thereto. When the raisable conveyerbelt 151 carrying the second multi-substrate strip stops S2, striplocation sensors (not shown) in the conveyer belt structure 152 relaythe location of the second multi-substrate strip S2 to the control means53′ in FIG. 18. The control means 53′ then indexes the laterallyindexable conveyer belt 160 in the direction shown by the arrows in FIG.19 to the proper location where it stops to receive the secondmulti-substrate strip S2 delivered thereto. The raisable conveyer belt151 is part of a structure connected to hydraulically operated portions155′ of hydraulic cylinder 155 which then move the belt 151 upward tolaminate the second substrate strip S2 on raisable conveyer belt 151against the first multi-substrate strip S1 above it. This processcontinues with the subsequent strips. The belt 151 is then lowered bythe pistons 155′. The sticking force of the adhesive bands B and B′ notyet fully cured, is desirably greater than the vacuum force holding thestrip on the belt. If not, vacuum pressure on the belt 151′ ismomentarily cut-off.

[0151] As this process continues, the laminated multi-substrate stripsnow forming a continuous web of laminated strips pass between thelaterally indexable belt 160 and a nip roller 170. The continuous webthen passes over an idler roller 172, under a dancer tensioning roller174, which tensions the newly formed web, and over another idler roller176 to a driven take-up reel 178. The speed of rewind reel 178 iscontrolled by the elevation of the dancer tensioning roller 174.

[0152] While the invention has been described with reference topreferred embodiments of the invention, it will be understood by thoseskilled in the art that various changes and modifications may be madeand equivalents may be substituted for elements thereof withoutdeparting from the broader aspects of the invention.

We claim:
 1. In an expandable and contractible cellular panel comprisedof a plurality of parallel, aligned, elongated tubular sections securedtogether at the median region of their adjacent longitudinal margins toform the panel, each of the tubular sections being made of flexiblesheet material to enable each tubular section to be flattened orexpanded into an open tube, the improvement wherein: adjacent tubularsections of the panel are made of a pair of substantially identicalseparate strips of sheet material from those forming the other adjacenttubular sections, the various adjacent pairs of strips being laminatedtogether along their confronting longitudinal margins, each strip beingmade of at least two separate flexible substrate sheets secured togetheralong their longitudinal margins and having different appearances, thecorresponding substrate sheets of the strips having correspondingpositions in the panel so that all the substrate sheets having oneappearance are on one side of the panel and those having a differentappearance are on the other side of the panel.
 2. An insulating panelfor covering windows and the like, the panel comprising a number ofelongated tubular sections of sheet material laminated together toprovide a panel comprising a plurality of elongated aligned cells, eachcell comprising an upper wall portion, a lower wall portion, a frontwall portion and a rear wall portion interconnecting front and rearmargins of the upper and lower wall portions, the improvement wherein:the top, bottom, front and rear wall portions of at least each adjacentpair of cells is made of at least two separate elongated strips of sheetmaterial joined together to form the cells, the separate strips formingeach adjacent pair of cells being strips different from those formingother adjacent pairs of cells, each of the elongated strips of materialmaking up the panel being of substantially identical size andconstruction and comprising at least two flexible substrate sheetssecured together along at least one of their confronting longitudinalmargins and made of differently appearing material, two of the differentsubstrate sheets of each strip being positioned in the panel to formfront and rear sides of a cell and presenting different appearances. 3.The insulating panel of claim 1 or 2 , wherein the substrate sheets ofthe strips forming the front wall portions of the cells of the panelhave a desirable aesthetic appearance and the substrate sheets of eachstrip that form the rear side of each cell of the panel have anappearance which aids in the reflecting of light impinging on the rearside of the panel from outside the window.
 4. The panel of claim 1 or 2, wherein the substrate sheets of each of the strips are made of athermoplastic material and are welded together along at least one oftheir longitudinal margins.
 5. The panel of claim 1 or 2 , wherein thestrips are laminated together by bands of adhesive.
 6. The panel ofclaim 4 , wherein the secured margins of the substrate sheets of eachstrip are of a thickness of the order of magnitude of the rest of thesheets so that the adjacent substrate sheets of each strip appear to bea single integral sheet with different appearing bands forming theopposite sides of the panel.
 7. The panels of claim 1 or 2 , wherein thetubular sections of the panel provide a vertically expandable andcontractible panel.
 8. The panel of claim 1 or 2 , wherein each tubularsection of the panel is formed by one of the multi-substrate sheets madefrom only a pair of differently appearing superimposed substrate sheetsof substantially identical size, the different substrate sheets of eachstrip being welded together along their opposite longitudinal margins toform a closed tube.
 9. The panel of claim 1 or 2 , wherein each tubularsection of the panel is one of the strips including only a pair of thesubstrate sheets of differently appearing material of the same lengthand width secured together along only one of the longitudinal marginsthereof and initially positioned in a common plane and the oppositelongitudinal marginal portions of each strip being folded over thecentral portion thereof to form an open tube, the open portion of thetube forming each tubular section of the panel is closed by itssecurement to the central portion of the folded strip of the adjacenttubular section of the panel.
 10. The panel of claim 1 or 2 , whereineach strip cut from a web is made of three initially separate substratesheets connected together along their longitudinal margins andpositioned one beside the other in a common plane, the longitudinalmarginal portions of the three-substrate web being folded over thecentral portion thereof to form an open tubular web, the centralsubstrate sheet of each strip being laminated to the folded over ends ofthe outer substrate sheets of the adjacent strip.
 11. The panel of claim10 , wherein the outer substrate sheets of each strip are made of alight-passing material, the central substrate sheet is made of an opaquematerial, and the substrate sheets on one side of the panel beingshiftable relative to the substrate sheets on the opposite side thereof,so that the opaque central substrate sheet of each strip can be pivotedbetween the position where it obstructs light to a maximum degree and aposition where it obstructs light to a minimum degree.
 12. The panel ofclaim 1 or 2 , wherein each of the strips is made of three initiallyseparate substrate sheets connected together along their longitudinalmargins, the central substrate sheet of each strip being opaque andforming a bottom or top wall portion of a tubular section of the panel,and the outer substrate sheets of each strip being made of alight-transmitting material and forming front and rear wall portionsrespectively of adjacent tubular sections of the panel, and thesubstrate sheets on one side of the panel are shiftable relative to thesubstrate sheets on the opposite sides thereof, so that the opaquecentral substrate sheet of each strip is pivoted between a positionwhere it obstructs light to a maximum degree and a position where itobstructs light to a minimum degree.
 13. The panel of claim 8 , whereinwhen the panel is oriented so that when the tubular sections extendhorizontally and are in vertically-spaced relation, each strip forms atop wall portion, a bottom wall portion, a front wall portion, and arear wall portion of one of the tubular sections, the top wall portionbeing laminated to the bottom wall portion of an adjacent tubularsection.
 14. The panel of claim 1 , wherein when each tubular section ofthe panel is oriented so that the tubular sections extend horizontallyand are in vertically-spaced relation, the secured together marginalportions of the substrates of each strip are located on the top orbottom wall portion of each tubular section of the panel where they arenot visible from the front or rear of the panel.
 15. The panel of claim14 , wherein the secured together marginal portions of the substrates ofeach strip are laterally offset from each other.
 16. The panel of claim15 , wherein the secured together marginal portions of the substratesform a slight thickening of the strip thereat so that, when the panel isvertically collapsed, the overall height of the collapsed panel is at aminimum because the secured together marginal portions of the substratesof such strip are laterally offset.
 17. The panel of claim 2 , whereinthe tubular sections of the panel are laminated together by a pair ofbands of adhesive spaced on either side of the center line of the topand bottom wall portions of each tubular section of the panel, so thatdrawstring-receiving holes can be drilled between such spaced bands ofadhesive without the adhesive being deposited on the drill bits or othertool used to form the holes.
 18. The panel of claim 14 or 15 , whereinthe secured together marginal portions of the substrates are securedtogether by welding the same together and wherein the tubular sectionsof the panel are laminated together by adhesive which extends over thewelded margins of such substrates to reinforce the same.
 19. In a methodof mass producing insulating panels for covering windows and the like,each panel comprising a number of elongated tubular sections of flexiblesheet material laminated together to provide a panel comprising manyelongated aligned cells, each of the cells, when extending horizontallyand in vertically-spaced expanded relation, being formed by top andbottom wall portions and front and rear wall portions connecting withfront and rear margins of the upper and lower wall portions of eachcell, the method comprising the steps of: providing at least twocontinuous substrate sheets made of differently appearing materials;securing at least one of the longitudinal margins of the two substratesheets together to form a continuous multi-substrate sheet web and,where necessary, performing other steps, to form a continuous tubularweb; laminating longitudinally-spaced tubular segments of the websevered or to be severed therefrom to form tubular strips forming thelaminated tubular sections of the panel when severed from the web, andsevering the segments of the web to form the panel of laminatedsegments, wherein the front side of the completed panel is comprisedonly of one of the substrate sheets having the same appearance and therear side of the panel is comprised only of the other of the substratesheets having a different appearance.
 20. The method of claim 19 ,wherein only a pair of the continuous substrate sheets of the differentappearing material are used to form the web, the substrate sheets beinginitially superimposed so that their opposite longitudinal edges arealigned, and the securing step secures together both of the oppositelongitudinal edges of the superimposed substrate sheets together to forma flat closed tubular web, then expanding the flat tubular web and thenflattening the same in a plane at a substantial angle to the plane ofthe original flat tubular web, so that the secured-together edges of thesubstrate sheets of each strip cut from the web will be located on oneof the top or bottom wall portions of a tubular section of the panelwhen the various strips cut from the web are laminated together and thepanel formed thereby is oriented so that the tubular sections thereofextend longitudinally and in vertically-spaced relation.
 21. The methodof claim 20 , wherein the second plane is less than 90° from theoriginal plane, so that when the flattening step is completed, the weldsare laterally spaced on one of the top and bottom wall portions of eachtubular section of the panel.
 22. The method of claim 21 , wherein thetubular strips are adhesively laminated together over the welds toreinforce the same.
 23. The method of claim 21 , wherein the step offlattening the tubular web in a plane less than 90° from that of theoriginal plane of the tubular web includes the steps of transitioningthe plane of the original web from an original horizontal plane to anupwardly extending plane and opening the tubular web and then flatteningthe web to form a horizontally flattened tubular web where the securedtogether edges are now located on opposite sides of a vertical planepassing through the center of the horizontally flattened web.
 24. Themethod of claim 19 , wherein the securing of the longitudinal margins ofthe substrate sheets forming each strip is accomplished by superimposingand aligning the corresponding longitudinal margins of the continuoussubstrate sheets and welding together at least one aligned pair of thelongitudinal margins of the superimposed sheets, and there is includedthe step of at least partially flattening any bulge which results fromthe welding step.
 25. The method of claim 24 , wherein after flatteningthe welded-together edges of the tubular web, the web is passed intension over a heated cambered plate, to minimize longitudinal bow inthe tubular strip and ripples at the welded edges of the substratesheets.
 26. The method of claim 19 wherein the laminated substratesheets forming the tubular web which form the front and rear sides ofthe completed panel are made of material of different thicknesseswherein the web is oriented and flattened so that its secured togetheredge or edges of the tubular web are on the top or bottom of theflattened tubular web which is then fed and guided between at least onepair of pressure-applying nip rollers, one of the rollers being mountedfor tilting adjustment in a vertical plane so that the side of theroller to engage the thicker substrate sheet of the web applies agreater pressure to the web than the other side thereof, and soadjusting the tiltably mounted nip roller to apply the greater pressureto the thicker substrate sheet so the web is guided for movement in astraight line.
 27. The method of claim 25 wherein the laminatedsubstrate sheet forming the tubular web which forms the front and rearsides of the completed panel are made of material of differentthicknesses wherein the web is oriented and flattened so that itssecured together edge or edges of the tubular web are on the top orbottom of the flattened tubular web which is then fed and guided betweenat least one pair of pressure-applying nip rollers positioned at bothends of the cambered plate, one of the nip rollers at each end of theplate being mounted for tilting adjustment in a vertical plane so thatthe side of the roller to engage one of the substrate sheets of the webapplies a pressure which can be adjusted relative to the pressureapplied by the other side of the roller which engages the othersubstrate sheet, and so adjusting the tiltably mounted nip roller toapply the desired pressures so that the web is guided for movement in astraight line.
 28. In a method of mass producing insulating panels forcovering windows and the like, each panel comprising a number ofelongated tubular sections of flexible sheet material laminated togetherto provide a panel comprising many elongated aligned cells, each of theelongated cells, when extending horizontally and in vertically-spacedexpanded relation, being formed by top and bottom wall portions andfront and rear wall portions connecting with front and rear margins ofthe upper and lower wall portions of each cell, the method comprisingthe steps of: providing at least two continuous substrate sheets made ofdifferently appearing materials; securing at least one of thelongitudinal margins of the two continuous substrate sheets together toform a continuous multi-substrate sheet web and performing one or moreother steps, if necessary, to orient the multi-substrate sheet web in aflat unfolded condition, where the substrate sheets of the web are in acommon plane, then folding the longitudinal marginal portions of the webso that the confronting edges of the folded-over portions of the web donot overlap to form an open tubular web which is then cut into stripsand the strips laminated to form the panel.
 29. The method of claim 28 ,wherein there are only two continuous substrate sheets made of differentappearing substrate materials which are secured together to form atwo-substrate sheet web, the securing and other steps includingsuperimposing the continuous substrate sheets so that at least one pairof their longitudinal edges are aligned, then welding the alignedlongitudinal edges of the superimposed substrate sheets together to forma multi-substrate open-tubular web and then unfolding the open-tubularmulti-substrate sheet web.
 30. The method of claim 29 , wherein thewelded portions of the unfolded web are flattened to produce amulti-substrate sheet web with a similar thickness throughout, thenfolding the outer longitudinal marginal portions of the multi-substrateweb over the central portion of the multi-substrate web so that theconfronting edges of the folded over portions of the web do not overlapto form an open tubular web which is then cut into strips and the stripslaminated to form same panel.
 31. The method of claim 20 , wherein thelamination of the tubular segments or strips includes the steps ofapplying longitudinally extending, laterally-spaced bands of adhesive toportions of the web which are to form one of the top and bottom wallportions of a tubular section of the panel when the tubular portions ofthe panel extend horizontally and are in vertically spaced relation, andpressing the adhesive-coated side of each of the segments of the webbefore or after severance therefrom against the side of the adjacentsegment of the web which forms or is to form an adjacent tubular sectionof the panel.
 32. The method of claim 19 , wherein there are providedone wide continuous opaque substrate sheet and two narrower continuouslight-passing substrate sheets; the securing of the continuous substratesheets together includes superimposing the three continuous substratesheets so that the wider opaque substrate sheet is in the middle of thesuperimposed stack of sheets, and one of the longitudinal margins of theopaque substrate sheet and that one of the light-passing sheets are inalignment and the opposite longitudinal margin of the opaque substratesheets and the corresponding longitudinal outer margin of the otherlight-passing substrate sheet are in alignment welding the alignedmargins of the superimposed opaque and light-passing substrate sheetstogether to form a three-substrate web and unfolding the originallysuperimposed sheets where all of the substrate sheets are in the sameplane; folding the outer light-passing substrate sheets over the opaquecentral substrate sheet to form an open tubular web; and then laminatingtogether the longitudinally-spaced segments of the tubular web, severedor to be severed therefrom, so that when the resulting panel is orientedso that the tubular sections thereof extend horizontally and arevertically-spaced relation, when the tubular sections are expanded, thelight-passing substrate sheets will form the front and rear wallportions of an expanded tubular section of the panel and the opaquesubstrate sheets form a common top and bottom wall portion of extendedtubular section of the panel, and the light-passing substrate sheet onone side of the panel be shiftable relative to the light-passingsubstrate sheets on the opposite side thereof so that the opaque centralsubstrate sheet of each tubular section of the panel can be shiftedbetween a position where light can pass freely through the panel towhere the opaque substrate sheets overlap one another to obstruct thepassage of light through the panel.
 33. The method of claim 32 , whereinthe lamination includes the steps of applying adhesive to the faces ofthe inturned marginal portions of the web which are to confront theopaque substrate sheet in the completed panel, and pressing theadhesive-coated side of each of the segments before or after they aresevered from the web against the side of the adjacent segment are toform the adjacent tubular sections of the completed panel.
 34. Themethod of claim 19 , wherein there are provided one relatively widecontinuous opaque substrate sheet and two narrower continuouslight-passing substrate sheets; the securing of the continuous substratesheets together include superimposing the three continuous substratesheets so that the wider opaque sheet is in the middle of thesuperimposed stack of sheets, one of the longitudinal margins of theopaque substrate sheet and that of one of the light-passing sheets arein alignment and the opposite longitudinal margin of the opaquesubstrate sheet and the corresponding longitudinal margin of the otherlight-passing substrate sheet are in alignment, welding the alignedmargins of the superimposed opaque and light-passing substrate sheetstogether to form a three-substrate web; the method further including thestep of unfolding the superimposed welded substrate sheets to form aflat unfolded web, cutting the flat web into strips and laminating thecut strips together by sequentially laterally shifting the strips fromtheir original longitudinally-spaced position and with their cut marginsin alignment and sequentially laminating them together in the same orderin which they were cut from the web, and then adhering eachlaterally-shifted cut strip to the strip cut immediately before it, sothat the outer longitudinal margin of one of the outermost light-passingsubstrate sheets of each strip is adhered to the strip just previouslycut from the web at the innermost longitudinal margin of thecorresponding substrate sheet thereof, and the inner longitudinal marginof the other outermost light-passing substrate sheet of each formerstrip is adhered to the latter adjacent strip at the outer longitudinalmargin of the corresponding outer substrate sheet thereof, wherein whenthe resulting panel is oriented so that the tubular sections thereofextend horizontally in a vertically-spaced relation and the panel isexpanded, one of the light-passing substrate sheets of each laminatedsegment of the panel forms the front wall portion of one of the cells ofthe panel, the opposite light-passing substrate sheets of that laminatedsegment will form the rear wall portion of the adjacent cell of thepanel, and the opaque substrate sheet of that laminated segment willform a common wall between two adjacent cells of the panel.
 35. Themethod of claim 34 , wherein the lamination includes the steps ofapplying bands of adhesive to longitudinally-spaced segments of thethree-substrate web along longitudinal bands where the strips areadhered together at the point described.
 36. The method of claim 20 or29 , wherein the securing of the continuous substrate sheets together iscarried out by welding of their longitudinal margins together with sonicwelders comprising a vibrating member which presses the substrate sheetsto be welded together against an anvil having a pointed profile, so thatthe substrate sheets being welded are severed at the location of thepoints on the profile of the anvil, producing a separated, selvedgedstrip on the side of the pointed profile adjacent the margin of thesubstrate sheets and welds together confronting marginal portions at thesuperimposed surfaces of the substrate sheets on the opposite side ofthe pointed profile of the anvil.
 37. The method of claim 36 , whereinthere is provided the step of flattening the welds at the longitudinalmargins of the three-substrate sheets before the segments of the webbefore or after they are severed from the web are laminated to the othersegments thereof.
 38. Apparatus for mass-producing cellular panels forcovering windows and the like, the panels comprising a number ofelongated tubular sections of thermoplastic, flexible sheet materiallaminated together to provide a panel comprising many elongated alignedcells, the apparatus comprising: first means for feeding along a givenpath two continuous substrate sheets of different appearance which areto form the visible front and rear sides of the panel; means along thepath for securing together at least a pair of continuous flexiblesubstrate sheets along at least one of their adjacent longitudinal edgesas the sheets are moved thereby and, if necessary, performing othersteps to form a tubular web where the opposite sides thereof are formedby the two continuous substrate sheets; and located along the path meansfor cutting equal length segments of the tubular web into tubular stripsand laminating the segments together to form the cellular panel when thetwo substrate sheets form the opposite visible sides of the panel. 39.The method of claim 19 wherein the securing step is the welding of thelongitudinal margin of the substrate sheets together.
 40. The method ofclaim 39 wherein prior to the lamination of the web segments, thetubular web is flattened and oriented so the welded longitudinal marginsof the tubular web are on the top or bottom of the flattened tubularweb, and the flattened side margins of the tubular web are formed into apermanent sharp fold by passing the web between a cylindrical anvilwhich has a central slot which confronts the central portion of the webincluding the welded margin of the substrate sheets, and a sonic hornengaging and pressing the longitudinal side margins of the flattened webagainst the cylindrical anvil.
 41. An apparatus for mass-producingcellular panels comprising a plurality of parallel, aligned, elongatedtubular sections secured together at the median regions of theiradjacent longitudinal margins to form the panel, each of the tubularsections being made of flexible thermoplastic sheet material to enableeach tubular section to be flattened or expanded into an open cellulartube, the apparatus comprising: first means for feeding to a weldingstation at least two continuous thermoplastic substrate sheets ofdifferent appearance which are to form the visible front and rear sidesof the panel; a welding station including welding means for heat weldingtogether the continuous thermoplastic substrate sheets fed to thewelding station by the first means, along at least one of their adjacentlongitudinal margins and where necessary, performing other operations toform a tubular web; and means for cutting equal length segments of thetubular web into tubular strips and laminating together the segments toform the panel.
 42. The apparatus of claim 41 , wherein the first meansincludes means for superimposing a pair of the continuous substratesheets which are made of the same width and aligning their superimposedlongitudinal margins; the welding means including means for welding theopposite longitudinal margins of the substrate sheets together to form aflattened tubular web; and there is provided web-reforming means foropening the flattened tubular web and reflattening the same in asubstantially different plane so that the welded together longitudinalmargins of the substrate sheets are now in the middle region of the flatopposite sides of the reformed web; the laminating means laminating themiddle regions of the latter opposite flat sides of the reformed webtogether, so that the welded margins of the longitudinally spacedsubstrate sheets which are later hidden from view in the completedpanel.
 43. The apparatus of claim 42 , wherein there is provided meansfor flattening the welded portions of the reformed tubular web before toproduce a tubular web of similar thickness throughout.
 44. The apparatusof claim 42 or 43 , wherein there is provided means for heating thewelded portions of the tubular strip to relieve stresses in the reformedtubular web.
 45. The apparatus of claim 42 , wherein the web-reformingmeans includes means providing a slot dimensioned to receive theoriginal flat tubular web and to direct the welded margins of thesubstrate sheets of the web in a given plane before the initially formedtubular web is opened to direct a first one of the welded margins of thesubstrate sheets on one side of a third plane, which is a referenceplane, and to direct the other welded margins of the substrate sheets ofthe original web to the opposite side of the reference plane before theinitially formed tubular web is opened; a guiding insert adapted to passand float within the opened initially formed web, the guiding inserthaving a pair of pointed projections in the reference plane which engagethe open web to expand the same in the reference plane and to keep thetwo different welded margins of the web on opposite sides of thereference plane; and means for receiving the guided web with the weldedmargins directed on opposite sides of the reference plane and flatteningthe web so that the directed welded margins of the web are on oppositeflat sides of the finally flattened reformed tubular web.
 46. Theapparatus of claim 45 , wherein there is provided a pair of outer guidemembers having grooves which confront and overlap in spaced relation thepointed projections of the guide members and dimensioned to receivebetween them and the pointed projections the opened tubular web.
 47. Theapparatus of claim 44 , wherein the heating means further includes aheated cambered plate over which the reformed tubular web is pulled. 48.An apparatus for mass producing insulating panels for covering windowsand the like, each panel comprising a number of elongated tubularsections of substrate sheet material laminated together to provide apanel comprising many elongated aligned cells, each of the elongatedcells, when expanded and extending horizontally and in vertically-spacedexpanded relation, being formed by top and bottom wall portions andfront and rear wall portions connecting with the front and rear marginsof the upper and lower wall portions of each cell, the improvement wherethe apparatus comprises: substrate sheet positioning and feedingapparatus described to receive at least two continuous substrate sheetsmade of differently appearing materials and conveying them along a givenpath; substrate sheet securing apparatus along the path positioned toreceive the longitudinal margins of the two continuous substrate sheetsand to permanently connect the margins together to form a continuoustubular web; web cutting and laminating apparatus along longitudinallyspaced positions to permanently connect longitudinally spaced tubularsegments of the tubular web severed or to be severed therefrom, to formsecured together tubular strips forming the laminated tubular sectionsof the panel when severed from the web, and to sever the segments of theweb to form the panel of laminated segments; and web positioningapparatus for positioning the web before the tubular sections aresecured together so that the front side of the completed panel iscomprised only of one of the substrate sheets having the same appearanceand the rear side of the panel is comprised only of the other of thesubstrate sheets having a different appearance and the permanentlyconnected margins of the tubular sections are in the laminated regionsthereof where the margins are hidden from view.
 49. The apparatus ofclaim 48 , wherein the web positioning apparatus includes substratesheet superimposing apparatus to superimpose only a pair of thecontinuous substrate sheets of the differently appearing material, thesubstrate sheets being thereby initially superimposed so that theiropposite longitudinal edges are aligned; and the securing apparatus ispositioned to be located along both of the opposite longitudinal edgesof the superimposed substrate sheets to connect them together to form aflat closed tubular web; and there is provided web-reforming apparatuspositioned to receive therearound the tubular web to open the same andincluding outer guide members to be positioned outside the expandedtubular web to re-flatten the same in a second plane at a substantialangle to the plane of the original flat tubular web, so that thesecured-together edges of the substrate sheets of each strip cut fromthe web will be located on one of the top or bottom wall portions of atubular section of the panel when the various strips cut from the webare laminated together and the panel formed thereby is oriented so thatthe tubular sections thereof extend longitudinally and invertically-spaced relation.
 50. The apparatus of claim 49 , wherein theguide members are positioned to re-flatten the tubular web in the secondplane which is less than 90° from the original plane, so that when theflattening step is completed, the points of the tubular section of thepanel are secured together and are laterally spaced from each other onthe top and bottom wall portions thereof.
 51. The apparatus of claim 48, wherein the laminating apparatus includes adhesive applicationapparatus along the path which deposits adhesive on the tubular websegments, so that the tubular sections of the panel are adhesivelylaminated together over the permanently connected margins to reinforcethe same.
 52. The apparatus of claim 48 , wherein the securing apparatusis apparatus for welding the longitudinal margins of a pair of thesubstrate sheets made of thermoplastic material together.
 53. Theapparatus of claim 52 , wherein there is provided along the pathfollowing the welding apparatus, weld-flattening apparatus to reducebulges which result from the welding operation.
 54. The apparatus ofclaim 53 , wherein web heating apparatus is positioned along the pathfollowing the welding apparatus to heat the web to relieve stressestherein and ripples at the welded edges of the substrate sheets.
 55. Theapparatus of claim 54 , wherein the heating apparatus is an outwardlybowed heated plate over which the web is pulled under tension.
 56. Theapparatus of claim 49 , wherein the web-reforming apparatus includes apair of spaced insert members positioned to be located inside and toexpand the tube, and either guide members positioned to be outside theexpanded tube to confront the insert members to keep the welded portionsin laterally spaced relation when the expanded tube is reflattened. 57.The apparatus of claim 52 wherein the apparatus includes guide means forsuperimposing the substrate sheets with the longitudinal margins thereofto be secured in alignment and the welding apparatus is a sonic weldingapparatus which includes an ultrasonic horn and an anvil between whichthe longitudinal portions of the superimposed substrate sheets to bewelded are fed, the anvil having a pointed profile which severs theportion of the longitudinal margins to be welded at points beyond thepointed portion thereof to produce a strip of waste material separatedfrom the rest of the superimposed substrate sheets being welded togetherand which anvil effects with the ultrasonic horn the welding together ofthe substrate sheets over a various band at points inside the pointedportion of the pointed anvil.
 58. The apparatus of claim 57 whereinthere is provided a sensing means projecting and detecting the presenceor absence of a space between the strip of waste material desirablyseparating from the superimposed substrate sheets and the portionsthereof being welded together, the sensing means being operable toeffect stoppage of the substrate sheet feeding apparatus when thesensing means detects the absence of the space indicating an operationfailure of the sonic welding apparatus.
 59. The apparatus of claim 58wherein the sensing means is a member located in the space where thestrip of waste material is supposed to separate from the weldedsubstrate sheets, the member being mounted for movement between a normalinoperative position to an operating position by the superimposedsubstrate sheets when the strip of waste material is not provided by thesonic welding apparatus.